The programme promotes good practice around sexual orientation issues and assists employers in recruiting and retaining lesbian and gay staff.

Francis Maude, Conservative Party chairman, said: “This seems to us absolutely the right thing to do. It’s not just about gay, lesbian and bisexual people. People should see us as a party that is inclusive and respectful of everyone in society.”

Ben Summerskill, Stonewall chief executive, said: “We’re delighted that the Conservative Party has agreed that it is the time to embark on this work. In order to recruit the very best people in the UK labour market in 2006, it’s necessary to demonstrate that you are a progressive employer.”

Stonewall’s Diversity Champions programme now has 240 members – including the Royal Navy, British Airways and Sainsbury’s – who between them employ nearly four million people. Recent recruits include consultants McKinsey, Manchester City FC and retailer Ikea.